Sound oscillations in the near field of the open working sections of two different wind tunnels are investigated. It was established by measuring the spectra of pressure fluctuations that the amplitude modulation of oscillations and the formation of their packets are typical of the cases considered. A more complete picture of the transient regime of flow in the mixing layer of a free jet in the working section of a wind tunnel is obtained. The well-known results of natural observations at the Sayano-Shushenskaya hydroelectric station are interpreted.
auto-oscillationsacoustic radiationwind tunnelTollmien–Schlichting waveshydroacoustic resonanceinfrasoundmodulationself-excitationnoise meter